Survival rate 28 days after hospital admission with first myocardial infarction. Inverse relationship with socio-economic circumstances.

OBJECTIVE: To study to what extent geographical differences of the mortality from ischaemic heart disease (IHD) can be accounted for by the 28-day case fatality rate (CFR) following first hospital admittance for acute myocardial infarction (MI) and whether the geographical pattern of survival has any relationship with socio-economic circumstances.
DESIGN: Register-based surveillance study.
SETTING: Seventeen residential areas in Malmö, Sweden.
SUBJECTS: All 5533 patients were admitted during 1986-1995 for a first acute MI at Malmö University Hospital. Main outcome measures. CFR is based on record linkage with national registers. Area-specific cardiovascular and socio-economic scores (SES) are based on previous cross-sectional studies.
RESULTS: In patients below 75 years of age, differences of the 28-day CFR accounted for 20-30% of the geographical variance in mortality from IHD. No corresponding association was found in older age groups. Patients from areas with low SES had the highest CFR, 23.8%. The odds ratios of fatal outcome for patients from areas with median and low SES (versus high SES) were 1.23 (95% CI: 1.01-1.50) and 1.25 (95% CI: 1.03-1.52), respectively (P for trend: 0.060). The strongest correlation was observed in men below 75 years of age (P for trend: 0.007). During the study period there was an improvement of the survival rate for patients from high and medium SES areas but no corresponding change for patients coming from areas having a low SES.
CONCLUSIONS: In patients below 75 years, geographical differences of the mortality from IHD were related to differences of the 28-day CFR following hospital admittance for a first MI. Rates of survival were inversely related to socio-economic circumstances in the patient's residential area.